An input device such as a mouse or a keyboard has been widely employed in a computer system for scrolling images shown on the display screen upwardly and downwardly. For example, by rotating a scroll wheel of the input device forwardly or backwardly, a specified control signal is generated to control the scrolling operations of web pages. In addition to the vertical scroll movement, it is important to achieve the horizontal scroll movement. For example, since the texts or graphs shown in the graphic-based window of the display screen usually fail to be fully browsed, the horizontal scroll movement is required to move the web page or the document in the left or right direction so as to display the desired image as required.
For facilitating a user to perform the horizontal scroll movement of the web pages shown on the display screen by operating the scroll wheel, a tilt scroll wheel module capable of being tilted leftwards or rightwards is developed. Such tilt scroll wheel module is applicable to an input device such as a mouse or a keyboard. Referring to FIG. 1, a schematic outward view of a mouse having a tilt scroll wheel module is illustrated. The tilt scroll wheel module 11 of the mouse 1 is positioned within an opening 101 of the main body 10 of the mouse 1, and the scroll wheel 12 is partially protruded from the outer surface of the main body 10 such that the tilt scroll wheel module 11 can be manipulated by a user. The scroll wheel 12 of the tilt scroll wheel module 11 can be rotated forwardly (as shown in the arrow F) or backwardly (as shown in the arrow B) to generate a control signal, thereby scrolling the image shown on the display screen upwardly and downwardly. Furthermore, the scroll wheel 12 can be pressed down (as shown in the arrow D), tilted toward the left side (as shown in the arrow L) or tilted toward the right side (as shown in the arrow R) so as to generate three other control signals.
Referring to FIG. 2, a schematic perspective view of the tilt scroll wheel module used in the tilt scroll wheel module of FIG. 1 is illustrated. The tilt scroll wheel module 11 principally comprises a scroll wheel 12, a rotating shaft 13, a carrier member 14 and a supporting member 15. The supporting member 15 has a receptacle 151 at the top side thereof. In addition, three switch units 16A, 16B and 16C are arranged under the bilateral sides of the carrier member 14 and under the rear end of the carrier member 14, respectively. The rotating shaft 13 is supported on a notch structure 141 of the carrier member 14, so that the scroll wheel 12 is rotatable along the rotating shaft 13.
Please refer to FIG. 2 again. The tilt scroll wheel module 11 further comprises lateral wing structures 142A and 142B at bilateral sides of the carrier member 14 and above the switch units 16A and 16B, respectively. In addition, the front and rear ends of the carrier member 14 are formed as protrusion rods 143A and 143B. The protrusion rod 143A is movably supported on the receptacle 151 of the supporting member 15. Whereas, the protrusion rod 143B is placed on the top surface of the switch unit 16C. In a case that the scroll wheel 12 is tilted toward the left or right side, the receptacle 151 of the supporting member 15 and the top surface of the switch unit 16C are used as the fulcrum portions such that the carrier member 14 is movable in the left or right direction. Meanwhile, the lateral wing structure 142A or 142B will touch and trigger the switch unit 16A or 16B. In addition, in a case that the scroll wheel 12 is pressed down, the receptacle 151 of the supporting member 15 is served as the fulcrum portion such that the protrusion rod 143B is moved downwardly to trigger the switch unit 16C.
The tilt scroll wheel module 11 mentioned above, however, still has some problems. For example, in the case that the scroll wheel 12 is not enabled, the protrusion rod 143B of the carrier member 14 is slightly in contact with the top surface of the switch unit 16C but the switch unit 16C is not triggered. If the scroll wheel 12 is pressed down, the switch unit 16C may be triggered by the protrusion rod 143B of the carrier member 14. Unfortunately, the depressing force applied onto the scroll wheel 12 is likely to improperly swing toward the left or right side due to a slippery hand or other reasons. Under this circumstance, the lateral wing structure 142A or 142B is likely to touch and trigger the switch unit 16A or 16B. As a consequence, the mouse 1 is suffered from an erroneous operation such as interruption of a current control signal or generation of an unanticipated control signal.
For solving the above problems, an input device with a tilt scroll wheel module was disclosed in a co-pending Taiwanese Patent Application No. 95100875, which was filed by the same assignee of the present application on Jan. 10, 2006, and the contents of which are hereby incorporated by reference.
Referring to FIG. 3, a schematic perspective view of the tilt scroll wheel module disclosed in Taiwanese Patent Application No. 95100875 is illustrated. In accordance with a feature of FIG. 3, the tilt scroll wheel module 21 further includes two confining members 27 and 28 for confining the carrier member 24 in position. The confining members 27 and 28 have complementary shapes. Due to the complementary shapes, the confining member 27 is shifted downwardly to be engaged with the confining member 28 while the scroll wheel 22 is pressed down to trigger the switch unit 26C. Therefore, the carrier member 24 is confined in position so as to avoid improperly swinging the carrier member 24 toward the left or right side or otherwise allow for tiny swing of the carrier member 24. Under this circumstance, the carrier member 24 will no longer trigger the switch unit 26A or 26B while the scroll wheel 22 is pressed down to trigger the switch unit 26C. Until the depressing force applied onto the scroll wheel 22 is eliminated, the scroll wheel 22 is moved upwardly and returns to its original shape due to a restoring force generated from the compressed switch unit 26C. Meanwhile, the confining member 27 is disengaged from the confining member 28, so that the carrier member 24 can be tilted toward the left or right side as required.
The tilt scroll wheel module 21 of FIG. 3 is effective for solving the problem occurred in the tilt scroll wheel module 11 of FIG. 2. However, there are still some drawbacks. For example, since two switch units are arranged at the bilateral sides of the scroll wheel and associated triggering components are required to trigger these two switch units, the volume thereof occupies much working space within the mouse and is adverse to space utilization. In addition, too many components increase the assembling time of mounting the switch units and the triggering components onto the proper positions of the mouse.
Therefore, there is a need of providing a mouse having a simplified tilt wheel encoding mechanism.